2-[7-(3,5-Dibromo-2-hy­droxy­phen­yl)-6-eth­oxy­carbonyl-2-oxo-5H-2,3,6,7-tetra­hydro­thio­pyrano[2,3-d][1,3]thia­zol-6-yl]acetic acid ethanol monosolvate

The title compound, C₁₇H₁₅Br₂NO₆S₂·C₂H₅OH, is the esterification reaction product of 2-(8,10-dibromo-2,6-dioxo-3,5,5a,11b-tetra­hydro-2H,6H-chromeno[4′,3′:4,5]thio­pyrano[2,3-d]thia­zol-5a-yl)acetic acid. Cleavage of the lactone ring and formation of eth­oxy­carbonyl and hy­droxy groups from its structural elements were observed. On the other hand, the carb­oxy­methyl group was not esterified. The H atom and carb­oxy­methyl group, both at stereogenic centres, show a cis conformation. The six-membered dihydro­thio­pyran ring adopts a half-chair conformation. All NH and OH groups participate in the three-dimensional hydrogen-bond network, which is additionally strengthened by C—H...O and C—H...S inter­actions. Intramolecular O—H...Br and C—H...O interactions also occur.